Process of manufacturing charcoal



(No Model.)

H. M. PIERCE. ROGESS OF MANUFACTURING GHAROOAL.

No. 272,976. Patented Feb.27, 1883.

Wifine-sa 6 N. PETERS. Phvio-lkhognaber. Wznhingiun. 0.1:v

UNITED STATES PATENT OFFICE.

HENRY M. PIERCE, OF CHICAGO, ILLINOIS.

PROCESS OF MANUFACTURING CHARCOAL.

SPECIFICATION forming part of Letters Patent No. 272,976, dated February2'7, 1883.

Application filed November 25, 1882. (No model.)

To all whom it may concern Be it known that I, HENRY M. PIERCE, acitizen'of the United States, residing at Ohicago, in the county of Cookand State of lili- 5 nois, have invented certain new and usefulImprovements in Processes of Manufacturing Charcoal and I hereby declarethe following to be a full, clear, and exact description of the same,reference being bad to the accompanying drawings, wherein- Fignre l is avertical section of a kiln enibodying my invention. Fig. 2 is ahorizontal section of the same on the line a: as, Fig. 1.

Like letters refer to like parts wherever they occur. v

The object of this invention is to facilitate and render more completethe carbonization of wood in acharcoal-kiln, to increase the yield ofcharcoal, and to preserve the kiln itself.

that wherever wood is fired in a charcoal-kiln at the top, as is thecommon practice, the carbonization begins at the top of the kiln andgradually works-downward toward the air-inlets. It is also well knownthat as the process continues the charring is retarded by the difficultyof drawing and holding the heat to the lower and central part of thekiln, In other words, it always takes longer time to char the bottomthird of the contents ofa charcoal-kiln than theupper two-thirds. Thisfact, I believe, is not alone owing to the tendency of heat to hang inthe top of the kiln, but also to the general effects of having theair-inlets and gas-outlets very near together, and both in thecircumference near the bottom of the kiln. The operation ofthisdefective construction by admitting air at the bottom and around thecircumference of a kiln is to draw the carbonization gradually downtoward these airinlets and gas-outlets, while a large amount of wood andbrands is left uncarbonized in the center and bottom of the kiln. Toremedy this difficulty the collier is often compelled to carry on a livecombustion of wood around the airinlets to complete the charring of thelower portion of the kiln. This course involves two objectionablefeatures first, the destruction by actual burning of a considerableportion of the wood;-and, secondly, great injury to the lower portion ofthe brick-work of the kiln It is well known among charcoalrmakers Aitself. A charcoal-kiln would be almost indestructible were it not forthe burning away of the lower interior part of its walls.

To remedy these complicated and injurious v effects I have devised aprocess wherein the carbonization is conducted by admitting thenecessary air-supply at or near the center and base of the charge,firing the charge above or at the top,and withdrawing the vapors, gases,850., evolved from the circumference and base of the charge, so thatwhile the carbonization approaches gradually the air-inlet or centralportion of the charge, the charge toward the circumference is undergoingcarbonization '6 5 from the effects of the highly-heatedgases, &c.,which escape in that direction, and the carbonization process isconsequently rendered uniform, while the brick work of the kiln isprotected.

In the drawings'is shown a kiln adapted to carry out my process, whereina flue or lines, I, extend from the outside of the kiln underneath thewall and floor of the kiln, terminating and opening upward through thecenter and bottom of the kiln. The termination of this air-flue I in thebottom of the kiln is provided with a raised shield or deflector, H,with air-outlets between the supports of the shield. This shield Hisprovided for thedouble purpose of scattering the air and protecting thefine I from filling up with coal, &c. The outer air inlet end of thisairflue is turned upward, and a register may be aflixed thereto toregulate the quantity of air demanded for 8 the carbonization of thekiln. In this way the charring can be controlled and made to proceedslower or faster as effectually as a stove or furnace can be regulatedby its dampers.

The operation in brief ofmy system is as fol- 9o lows: The kiln A beingcharged and doors luted up, the wood is fired through the opening X inthe top of the kiln. This opening is then closed and air admittedthrough the register Y of the air-fines, combustion of portions of thewood commences, heat is thereby evolved, and the ob arrin g begins. Thisprocess continues strictly in conformity with the wellknown fact thatthe charring or carbonization progresses steadily toward thepoints ofair-snp- Ico ply H. As by my process air is admitted through the bottomand along the center of gases through the wood along the sides of thekiln on their way to their out-lets 0 in the circumference ot' the kiln,so that the carbonizing progresses uniformly throughout the entirecharge.

The two great agencies for carbonizing wood in a charcoal-kiln are,first, the heat evolved by the absolute combustion of portions of thewood and gases, and, second, the hot volatile gases in the passagethrough the wood to their outlets. In the old system both of theseagencies tend to draw carbonization toward the circumference of thekiln, and on account of the close proximity of the air-inlets andgasoutlets the central portion of the kiln is deprived, first, of theheat generated by direct combustion; second, by the heat of the volatilegases, which, especially toward the close of the operation, escapealmost as soon as gencrated. In my system, however, the central portionsof the wood are charred by the direct heat, and the more outwardportions by the hot volatile gases in their passage to their outlets inthe circumference of the kiln.

I am aware thatin the manufacture of charcoal it has been customary tofire the charge or heap at the top and to withdraw the vapors, &c., fromthe base and circumference of the charge,as well as toadmittheair-supplythereat, and do not herein claim the same, for thereason that in all such cases the tendency of combustion istoward theair-inlets, in which direction the carbouization is already progressingsatisfactorily, because the heated gases, &c., pass in that direction asthey escape, and as aresult leave the central portions of the charge tocnrbonize more slowly and less satisfactorily. By my method, on thecontrary, the combustion is held to the center of the kiln, (as the tiretends toward the air-supply,) while the outer layers of the charge arecarbonized by the passage of the highly-heated gases, &c. Consequentlycarbonization goes on uniformly throughout the kiln, and terminatesuniformly and without the loss which often occurs where the outer layersare carbonized before the cen ter of the charge.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is-

In the manufacture of charcoal, the method herein described ofconducting the carbonizing process, which consists in admitting theair-supply at or near the center and base of the charge, firing thecharge ator near the top thereof, and witl'idrawing the gases and vaporsfrom the base and circumference of the charge, substantially as and forthe purpose specified.

In testimony whereof .I afiix my signature, in presence of twowitnesses, this 20th day of November, 1882.

HENRY M. PIERCE.

NVitnesses:

F. W. RiTTER, J 1-., H. B. MotiL'roN.

